1. Field of the Invention
The invention relates to a matrix pin print head with several print pins, which can each be moved forward into print position by way of a separate magnet drive, which print pins are resting at an element of the magnet drive transferring the advance motions, and which print pins can in each case be moved backward by way of a spring force, wherein each print pin exhibits a print pin head rigidly connected to the print pin.
2. Brief Description of the Background of the Invention Including Prior Art
The connection between the print pin and the print pin head is of substantial functional and production technological importance in a matrix pin print head. Print pins are known, where the print pin head is connected to a steel ball and a half ball or a disc made of metal, which in each case are injection molded with plastic. The shape of the print pin head corresponds then to a cylinder with a ball shaped contact face resting opposite to the armature arm.
Considerations have been made to produce the print pin head without metal, without steel ball, or without half ball, and to immediately injection mold the print pin with plastic. It also would be conceivable to furnish a print pin, made of tungsten, tungsten carbide, or sintered steel, with a print pin head made of metal. Such a structure, however, would not be very wear resistant. The armature arms strike in each case onto the print pin head and the print pin head has to transfer thereby the print impact force onto the print pin. Such a arrangement results in certain wear mechanisms. A high face pressure is developed between the element, transferring the forward motion of the magnet drive such as the armature, and the print pin head. Caps, or the like, placed on a steel ball, are released by deformation. Abrasion and attrition occur between the element, transferring the advance motion, and the print pin head at the contact face and, in the course of time, a contact face is formed which is adapted to the motions. In addition, an also wear causing relative motion takes place between the element, transferring the advance motion, and the print pin head.